[Start-up of full-scale UASB reactors].
The UASB reactors treating high-temperature citric acid wastewater could be started up in the alternation of mesophilic and thermophilic ranges because the local climate changed greatly by seasons. The reactors were started up in mesophilic range, and the total efficiency of the two-stage reactors reached 77%-86%; when the temperature of reactors reached 44 degrees C-45 degrees C, the reactors were operated in thermophilic range, and the total efficiency of the two-stage reactors reached 84%-93%; the reactors were re-operated in mesophilic range after closing about 38 days, and the total efficiency of the two-stage reactors reached 82%-96%. The start-up in the alternation of mesophilic and thermophilic ranges of the full-scale UASB reactors and the characteristics of mesophilic and thermophilic granular sludge were reported in this paper.